"My decision not to finalize negotiations on a new deal with Walkinshaw Andretti United is one that I've not taken lightly given the close personal friendships I've developed within the team, but the time has come to take on a new challenge," said Courtney.

"I love this team. WAU's been my home for nine years, and we've been through a lot together, but an exciting chance has presented itself, and it just couldn't be ignored."

WAU part-owner Ryan Walkinshaw added: “James has been a great member of this team for nine seasons, and we’ve shared some fantastic times together.

“I’m sure we will all miss his vibrant personality and smile around the garage, but we are looking forward to finishing our time together on a high for the remainder of the 2019 season.

“We all wish him the best for the future, he will always be a friend of the team and my family.

“We look forward to announcing a new WAU driver to our fans very soon.”